Heating stove



0d. 20, 1936. W, D. 4MERILL 2,058,094

HEATING STOVE Filed Fb. 25, 17936 2 Sheets-Sheet 1 Arwen/vio@ Oct. 20, 1936.

W. D. MERRILL HEATING sToVE Filed Feb. 25, 1956 2 Sheets-Sheet 2 HHH Patented Oct. Z9, i935 UNITED STATES PATENT OFFICE HEATING s'rovii 'y Wiuiam D. Merrill, Everett, Wash. Application February 25, 1936, Serialv No. 65,719 claims. (crise- 161) This invention relates to heating stoves and particularly to that class of stoves in which an airduct'is provided extending through the body of the stove and having an inlet opening and one Y yor more outlet openings whereby the air of the rocnrrnay be circulated through the stove and absorb heat therefrom and then discharged into` walls of the stove, the lower end of this air'` heating chamber being supplied with air from two air ducts disposed-on each side ci the re Y space, open at their forward ends and extendingl rearward and discharging into the rear lower portion of the air chamber.

chamber as tovcause the heat given oi by the fuel to be directed upward and then rearward in a circuitous course and to provide means for retarding the movement of the heated'pro'ducts 2510i combustion up through the stack so asto permit heat radiation from these products of combustion of heat which has not been absorbed by the air in the air chamber' and air ducts.

Other objects will appear in the course of the following description. I

My inventionis illustrated in the accompanying drawings Vwherein Figure 1 is a vertical sectional view ofimy improved stove on'the line I-lof Figure 3 VligureZ isa section on the linev 2v2 of Figure 1; A, Figure 3 is a sectionon' 'the line 3-4-3 of Figurefl;

Figure 4 isa fragmentary vertical section of 'the` lower portion of a grated stove with the wall oftheair conduit broken away;

'Figure 15 is a se'ctionon vthe line 5-'5 of4 Figure 4. l t Referring to' thesej'drawingsyit will be seen -that thestove comprises a more orless rectangular' shell, though I do not wish tob'e limited to the' exact shape'of 4this outer shell, this shellv providing' a bottom wall IIl, `a front wall Il, two side walls I2, a rear Wall I3, Vand'Y a top wall I4. 3For awood stove, these walls may be made 'of sheet material. For a-v coal stove; the shell should be cast and the walls be of thickerjmaterial. v The iront wall above "the bottom vFigure l, is; provided `with a fuel'door YI5 of any;V Isuite-blefA constrl'icti-onV but shown as being a fdo`0r- A further object is to so construct the air,

hingedat the side edge. Below this fuel door the `middle-of the'front is vprovided with an air inlet-opening having a damper I6 of any suitable construction. This damper i6 may be constituted by adoor-,whichvmay be opened to remove ashesor it may bey placed to admit air to the rear of the combustioni chamber according to tlfieiffuelused.V V At the rear portion of the top sheet I4 of the stove, there is provided a iiue thi-mble Il which preferably extends downY into the stove, as shown in full `lines in Figure l, and of course extends above the top of the stove so that the ue may be connected thereto. This thi'mble may have ajcollar I8 riveted tothe top sheet of thefstove or may be formed in any suitable lmanner: I -do not `wish `to be limited to the positioning of this flue opening in the'top ofA the stove as it might be disposed at the upper end of the rear wall of the stove,

Extend-ing upward from the bottom wall I0 adjacent the side walls I2 but spaced therefrom are the air duct walls i9. These walls extend downto the bottom sheet Ill and at their upper ends the wallsare deflectedk outward and upward vat `2li` and riveted or otherwise attached to theside'walls. The wall 20 of each air duct wall I9" extends upwar'dand rearward, as shown in l'igureI l, and the wall I9 terminates short of therear wall |73. The bottom plate I-D of the stovel isgform'ed at its forward end with inlet openings 2|" whereby the air of the room may passupward into thev air ducts 22 formed between the walls I9 and the` outer walls I2 of the 'stove. It will be seen thatv the space between "theseV walls 19 constitutes either the re spacewherein fuel may be disposed as in wood stovesjor mayjconstitute the repot if a grate islused'y above thefloor I0 `and below the openingfof the fdoor I5', as shown in Figure 5.

,lDispos'ed-abovethe fire space is an air chamber designated 23'fporme`d vby a lower wall 24 and an upper wall 25',;thewa1l 24 extending upward and rearward in a reverse curve to a point adjacent to but spaced from the front wall of the stove andth'en ,being curved around and merging into thewallzf, as at 26. The wall 2 5 extends rearwardto'a'point beneath the flue'thimble Il and then is exten'dedupward and rearward into abutting relatiorrtov the rearwall I31of the stove. At thepoint of junction of the walls 24 and 25, there-are'` vdisposed two openings 21 which discharge 'through the walls I2 to the air of the room; The wall 24 and the wall 25` extend entirely acrossthefwidth of the stove, or in other Words; -from one side I2 to the other side I2 and siii' between the inner walls I9 of the air ducts, the wall 24 is carried downward at 28 to the bottom sheet I0 of the stove, and this bottom sheet is provided with an opening 29 permitting the inlet of air into the space between the partition 28 and the wall I3. Thus the air chamber 23 has three sources of air, namely, the two openings 2| in the forward end of the bottom I0 and the single opening 29 in the rear end of the bottom I0.

It will be seen that the fire chamber or space 3|) is disposed immediately below the lower wall 24 of the air chamber 23 so that the air chamber receives directly the heat or heated products of combustion uprising from the fuel and that these heated products of combustion are directed upward and forward, as shown by the arrows in Figure 1, against the under face of the wall 24 and then upward between the portion 26 of the air chamber wall and the front plate of the stove. Then these products are directed rearward over the upper wall 25 of the air chamber 23 and so out through the flue thimble II. Because of the fact that the flue thimble I'I is extended downward into the stove, the outow of the heated products of combustion is retarded and these products are forced downward into more intimate contact with the upper wall 25 than otherwise would be the case. Inasmuch as this upper wall 25 curves upward and rearward, the flow of the products of combustion will very closely approximate the contour of this wall 25 so that the air within the air chamber 23 will be directly heated along the entire circuitous course taken by the products of combustion. The air entering the openings 2| and passing along the air ducts 22 will likewise be heated by the heat radiated from the re against the lining walls I9 and 20. By making the-upper walls 20 of the air duct downwardly inclined or downwardly and inwardly curved, the lodgement of ashes or fuel upon these upper walls will be prevented to a large Vinterior of the air chamber.

extent.

The stove is illustrated as being mounted upon legs as usual, thus permitting the free entrance of air through the openings 2| and 29 into the This stove embodies two methods of securing heat from the fuel, namely, by circuitous circulation of the currents of heated air or combustion products which are prevented from passing outward in a direct line to the iiue but are retarded by the circuitous course they are obliged to take and by the lowered stack opening. Second, this permits the heat to be radiated from the side, front and rear walls of the stove as well as it permits the heat to be absorbed by the cool air passing through the air ducts 22 and through the chamber 23. Because of the peculiar shape of the lower wall of the air ue, the heat currents are deflected forward and upward against the whole lower face of the wall 24, exposing this whole lower wall of the air chamber 23 to the most direct and most intense heat. Because of the fact that the lower wall of the air chamber is in line with the most intense heat in the combustion chamber and because of the fact that the lower end of the air chamber is open and communicates with air ducts which open through the bottom of the stove, the circulation starts from a point as near the floor as is consistent with operations.

The walls 24, 25 and 26 of the air chamber 23 may be made of thin sheet metal or of heavier material and the same is true of the walls I 9 and 20. The. walls of the air chamber are spaced from each other according to the heating capacity of the unit and fill the combustion chamber horizontally to the amount of space equal to the distance between the lower and upper wall of the heating chamber and extending from a point in front of the rear air intakes to the upper end of the discharge ports or openings Z'I in the shell of the stove. This stove may be used for coal, gas, oil, briquettes or for electrical heating by the installation of the necessary grates, burners or electrical heating unit and can be used either as a stove or hot air furnace, heating pipes being carried in this instance from the ports or openings 2'I. In actual practice, this stove has been found to provide a maximum of heat with a relatively small amount of fuel and secures more radiation than other stoves constructed along the same line.

In Figures 4 and 5, I have illustrated how the principle of my construction, as shown in Figures 1 to 3 may be applied to a coal stove or a stove having a grate. In this form of my invention, the air ducts defined by the walls I9a and 2|)a are disposed with the floors of these air ducts on a level with the grate 3|. At the forward ends the ducts extend downward and open through the stove bottom I9 at 2| e. The space below the grate, of course, constitutes the ash pit and at the rear a vertical duct 2821 opens into the air chamber 23 (not shown) in Figures 4 and 5, this vertical duct being open at its lower end, as shown in Figure 4.

The walls of the air ducts are to be made of no heavier metal and of the same material as the wall 24, because the flow of air through these air duets eliminates the necessity of the heavy refractory linings used in ordinary stove construction. The continuous flow of cold air through the ducts absorbs the heat that radiates through the wall 24 and through the walls I9 or I9. The higher the temperature in the re box, the faster the air current flows through the ducts and through the air chamber and the temperature of the air rises as it ows towards the discharge ports 2'I.

It will be necessary at all times, regardless of the fuel used, that these walls I9, I9e, 24 and 25 be arranged to present the greatest surface to the heat generated within the fire box in order to get the maximum of air flow.

I have before stated that this stove might be used with oil heaters or with electrical heaters. In this case, the burners or heating elements will be so placed as to apply the maximum of heat generated to the side faces of the walls I9 and the air chamber 23 at points as near as possible to the openings 29 and 2| through the stove bottom.

The cross sectional area of the air chamber 23 determines the flow of air and should be, of course, graduated according to the designed cubic air flow of a stove to meet the requirements of the space to be heated. Therefore, it is 0bvious that the area of the'air chamber 23 must be co-ordinated with the size of the openings 2|, air ducts 22, opening 29 and discharge ports 21.

As before remarked, I do not wish to be limited to the exact form of the stove nor to the details of construction except as they are called for in the appended claims.

What is claimed isz- 1. A stove including an outer shell constituting front, rear, side, top and bottom walls, a partition extending transversely across the interior of the shell from one side wall to the other sidewall and extending from a pointadjacent -to but spaced from the rear wall upward and forward to a point spaced from the front wall and then extending rearward to the rear wall, said partition defining an upwardly and forwardly directed air heating chamber, the forward upper end of the chamber having outlet openings, lining walls extending parallel to and engaged with the side walls of the stove and defining air inlet ducts opening at their forward ends to the exterior of the shell and at their rear ends discharging into the rear end of said air heating chamber, the front wall of the shell having a fuel door and below the fuel door having a draft inlet opening and damper, the upper rear portion of the shell having a iiue opening.

2. A stove including an outer shell providing front, rear, side, top and bottom walls, a wall defining an air chamber extending upward and forward and extending entirely across the space between the side walls, the lower wall of the air chamber terminating short of the rear wall of the shell and extending downward to the bottom of the shell, means forming air passages extending rearward from the front of the shell and discharging into the rear end of the air chamber, the passages opening at their forward ends to the exterior `of the shell, the top wall of the shell having a flue Vthimble extending downward into the shell, the front wall of the shell having a ue door, and a draft damper below the flue door. 1

3. A stove including anr outer shell providing front, rear, side, top and bottom walls, a partition extending upward from the bottom wall adjacent the rear wall, then extending upward and forward to a point adjacent the upper portion of the front wall of the shell, then extending rearward and then upward and rearward to the rear wall of the shell, the top wall of the shell immediately above said upward and rearward portion of the partition being provided with a flue opening defined by a downwardly depending thimble, the said partition defining an air chamber extending the full width of the shell and being attached to the side walls Ythereof, the shell having openings into the interior of the air chamber at the forward endv thereof, lining walls extending upward frorn the bottom wall of the shell and then inward to the side walls thereof and extending rearward from the v front end of the shell to the lower end of said partition, the lining walls defining air ducts discharging into the lower end of said air chamber, the bottom wall of the shell at its forward end being provided with air inlet openings discharging into the forward ends of the air ducts, the rear end of the bottom wall of the shell at its middle between the said air ducts having an air opening discharging into the lower portion of the air chamber, the front of the shell having a fuel door and a draft damper below the fuel door.

4. A stove including an outer shell constituting front, rear, side, top and bottom walls, a wall defining an air chamber, the wall extending transversely across the interior of the shell from vone side wall to the other side wall and extending from a point adjacent to but spaced from the rear wall upward and forward to a point spaced from the front wall and then extending rearward to the rear wall of the shell, the forward upperV end of the air chamber having outlet openings discharging through the shell, means forming air ducts extending parallel to the side walls of the stove, opening at their forward ends to the exterior of the shell and at their rear ends discharging into the rear end of the air heating chamber, the walls of said air ducts being disposed level with the fire chamber of the stove.

`5. A stove including an outer shell constituting front, rear, side, top and bottom walls, a wall defining an air chamber extending transversely across the interior of the shell from one side wall to the other side wall and extending from a point adjacent to but spaced from the rear wall upward and forward to a point spaced from the front wall and then extending rearward to the rear wall of the shell, the forward upper end of the air chamber having outlet openings discharging through the shell, a grate disposed within the stove above the bottom thereof, and means forming air ducts on each side of the grate, the lower walls of the ducts being on the same level as the grate, the forward ends of the air ducts opening to the exterior of the shell, the rear ends of the air ducts discharging into the rear end of the air heating chamber.

WILLIAM D. MERRILL. 

